Stop motion for knitting machines and the like



July 21, 1942. w. E. STANLEY ETAL 2,290,257

STOP MOTIQN FOR KNITTING MACHINES AND THE LIKE Filed May 13, 1941 2 Sheets-Sheet 1 \H 34 218 xii 5% ,12

ATTOF/VIVJ' y 1942- w. E. STANLEY ET AL 2,290,257

STOP MOTION FOR KNITTING MACHINES AND THE LIKE Filed May 13, 1941 2 Sheets-Sheet 2 Patented July 21, 1942 2,290,257 s'ror MOTION FOR KNI'I'IING MACHINES AND THE LIKE William Ewart Stanley and Cyril Houghton I Edwards, Spondon, near Derby, England, assignors to Celanese Corporation of America, a

corporation of Delaware Application May 13, 1941, Serial No. 393,168 In Great Britain June 7, 1940 9 Claims. (Cl. 66-166) This invention relates to stop motions for knitting machines and the like, and is particularly concerned with stop or detector motions for warp knitting mac es.

According to the present invention a stop or detector motion for a knitting machine or the like comprises a photo-electric cell, means for traversing said cell repeatedly across a fabric being formedon the machine and close to the line at which said fabric is being knitted, means for directing light coniing from said fabric into said cell, and operative means controlled by said cell and adapted to act on undue variation of the amount of light entering said cell by reason of faulty fabric. 'By this means the whole of the fabric may be traversed by the cell and if a thin a focused illumination travelling with the cell Where the light source is on the same side of th fabric as the photo-electric cell, use may be madl or thick place shouldbe encountered at any point in the fabric, dueto a missing thread, or an extra thread, or any other fault, the light transmitted through orrefiected from the fabric, and consequently the light entering the cell, will alter in intensity and the operative means will act, either to stop the machine or to give a warning signal,

The photo-electric cell employed for the purpose of the present invention is preferably enclosed by a suitable casing having a narrow slit which faces the fabric and is close to the surface thereof as the cell is traversed across the fabric. The slit, which should extend parallel to the length of the fabric being formed, should be of suflicient length to cover the short length of fabric formed in the time between successive passages of the cell, so that every part of-the fabric is covered. In conjunction with the cell, and connected therewith by a suitable cable for sup plying current to the cell, a suitable valve amplifier and relay may be employed so that the small variation of current occurring when the resistance of the cell varies on account of a change of light intensity may be sufiiciently intensified to be used for stopping the machine or giving the required signal. The sensitivity of the cell and associated mechanism should, of course, not be so high as to operateas a result of any variations in opacity that may be expected in a satisfactory fabric, and it'may be necessary to make the sensitivity adjustable to deal with fabrics of different types and/or patterns. This may be done by adjusting the width of the slit, and/or" by'suitable resistances in the cell or relay circuit.

The light by which the photo-electric cell is actuated may be' supplied from a 'source either on the same side of the fabric as the cell, or on the opposite side, and eitherin the form of a gen- I detail with reference to the accompanying drawof the reflection of thelight from the, fabric bacl into the cell, or alternatively a mirror may be dis posed on the opposite side of the fabric to reflect the light back into the cell. In the first case the light entering the cell does not pass through the fabric, but is reflected once by the fabric itself and in the second case the light passes twice through the fabric before entering the cell.

- For the purpose of traversing the photo-electric cell and if necessary the source of light,

.across the fabric a traversing carriage may be employed, provided, in the case of straight bar machines, with a suitable reversing mechanism. The stop mechanism according to the invention forms a convenient unit that may readily be attached to a straight bar machine such as a warp knitting machine. The mechanism usually provided on such machine for stopping the machine may be adapted, by means of suitable electrical and mechanical connections, to stop the machine under the control of the device. The only other modification necessary to the machine is theprovision of one or more rails or bars across the width of the machine on which the traversing carriage rrlay and the provision of the necessary driving mechanism for the carriage. The device is particularly convenient in warp knitting machines in which the threads are fed by two or more guide bars. In such machines a mechanical detector is apt to, fall where a thread is missing in one bar, since the continuity of the fabric structure is maintained by the threads of other bar or bars and no actual hole, such as could be deinvention however, notwithstanding the contlnuity of the fabric structure, the fabric becomes more transparent where a thread is missing, so that the device according to the present invention is especially well adapted to deal with such cases By way of example two forms of stop motion mechanism suitable for use on a straight bar warp knitting machine will now be described in greater ings, in which Figure 1 is a side elevation;

Figure 2 is a front elevation of one form of mechanism;-

Figure 3 is a diagrammatic side elevation-of a warp knitting machine showing the application of the mechanism shown in Figures 1 and 2;

eralillumination of the fabric, or in the form of 55 Figures 4 and 5 are a side elevation and a front elevation respectively of a further form of mechanism; and

Figure 6 shows a detail of the mechanism shown in Figures 4 and 5.

Referring to Figures 1 to 3 the knitting elements of the machine are shown in Figure 1, i. e., the needles I, the sinkers 2, the presser 3, and the guides 4 of a two-bar warp knitting machine. The guides 4 lead the warp threads 5 to the needles I by which the Warp threads are knitted into the fabric 6 which proceeds to a take-up device 1 and is. wound in a roll 8. On its way from the needles I, the fabric 6 passes over a mirror 9 extending the whole length of the machine and above the fabric 6 parallel to the mirror 9 is a threaded shaft l6 mounted in bearings H in an extension |2 to the side frame |3 of the machine. 7

The threaded shaft I0 is driven from the handwhecl shaft l4 of the machine. For this purpose pulleys I5, I 6 and a belt I! are provided which convey the drive to a bevel gear l8 secured to the pulley I6, and the bevel gear I8 engages with a bevel gear l9 mounted on a shaft 26 carrying a further bevel gear 2| engaging with two bevelgears 22, 23 loosely mounted on the plain end of the shaft l0. One or other of the bevel gears 22 is clutched to the shaft l0 by the provision of clutch cones 24, 25, secured to the gears 22, 23 and a clutch member 26 splined to the shaft l0 and brought into engagement with one or other of the clutch cones 24, 25 by means of a fork 21 mounted on a shaft 28 parallel to the threaded shaft I0.

Resting on the threaded shaft I0 is a carriage 29 which is cut with a thread engaging with the threads of the shaft |0, so that it may be driven to and fro by the rotation of the shaft l0 alternately in opposite directions. The carriage 29 engages only with the upper side of the threaded shaft In, which enables the shaft to be supported underneath at several points along its considerable length. Depending from the carriage 29 are two rods 30 to which are secured a lamp 3| throwing a focused beam of light on the mirror 9, and a photo-electric cell 32 adapted to receive the beam of light as it is reflected from the mirror 9 after passing twice through the fabric 6. The carriage 29 is guided and located by means of two upwardly extending lugs 33 engaging with the shaft 26. These lugs also serve to engage a stop member 34 secured to the shaft 28 whereby, when the carriage 29' reaches the end of its motion, the shaft 28 is moved longitudinally carrying with it the fork 21. The movement of the fork' 21 disengages the member 26 from one of the clutch cones 24, 25.and

engages it with the other, thereby reversing the direction of drive of the shaft l0 and the direction of motion of the carriage 29. A similar stop is provided on the shaft 28 at the other end of the machine, both stops being adjustable to accommodate the traverse of the carriage 29 to the width of the fabric being knitted.

By these means the carriage 29 together with the lamp 3| and photo-electriccell 22 are traversed to and fro across the width of the fabric 6 so" that any undue irregularity in the opacity of the fabric 6 gives rise to a variation in the intensity of the lightreceived by the cell 32.

Figure 3 is a general view showing how the mechanism is fitted to the frame of a straight bar warp knitting machine. The frame I 2 carrying the shafts l0 and 28 is secured at 35 to the vertical brackets carrying the fabric roll 8 and at 36, 31 to the end frame of the machine. The.

photo-electric cell 32 is connected by a suitable cable to an amplifier in the manner described hereafter with reference to Figures 4 and 5, the amplifier being adapted to intensify small variations of current occurring as the resistance of the cell 32 varies, and to employ the amplified current either to stop the machine or to give a warning signal when a fault in the fabric has occurred.

Referring to Figures 4, 5 and 6 the knitting elements I and 4 are shown as in Figure 1. In the form of apparatus shown in these figures no focused illumination is employed, the general illumination of the upper surface of the fabric 6 being relied on for the purposes of the invention. Below the fabric 6 as it leaves the needles I is disposed a photo-electric cell 4| mounted on a carriage 42 which slides on two horizontal angle bars 43 extending across the width of the machine. The bars 43 are carried at intervals on rods 44 secured to a cross-member 45 connecting the frames I3 of the machine.

The carriage 42 is driven by means of a double chain 46 passing round pulleys 41 at each end of the machine, the pulley 41 shown in Figures 4 and 5 being mounted on a shaft 48 carrying a bevel gear 49. The bevel gear 49 engages with the bevel gear 56 mounted on a shaft 5|, which is carried in bearings 52 secured to the under side of the bars 43. The shaft 5| is driven by means of pulleys 53 and 54 from the hand-wheel shaft M of the machine.

The carriage 42 is connected to one run or the other of the double-chain 46 by means of a half sprocket 56 freely mounted on a spindle 51 secured to the top plate 58 of the carriage 42. The sprocket 56 has a projection 59 adapted to engage with one or other of two pins 60, 6| which project downwardly from a slide 62. The slide 62 is held against the under side of the top plate 58 by means of a guide-member 63, the spindle 51 passing through an elongated hole 64 in the slide 62. At each end of the machine is provided a stop pin 66 carried on a bracket 61 mounted on a shaft 68 extending across the machine. When the carriage 42 reaches the end of its travel across the machine the stop pin 66 engages the slide 62 and holds 'it still while the carriage 42 continues its motion. In this way the extension 59 on the half sprocket 66 disengages the pin 69 with which it is engaged and is free to rotate until it engages the other pin 6|. The half sprocket 56 is thus permitted to rotate one half a revolution whereby its teeth disengage one run of the chain 46 and engage the other. Further rotation of the sprocket 56 is then prevented and the carriage 42 is effectively secured to the other run of the chain 46 whereby it is driven in the opposite direction. The positions of the brackets 61 and stops 66 are adjustable, in accordance with the width of the fabric being knitted.

The photo-electric cell 4| is thus driven backward and forward across the width of the fabric and receives light passing through the fabric.

I length of fabric produced while the photo-electric cell crosses the fabric in both directions is less than the length of the slit 69. In this way every part of the fabric is scanned twice and, in the event of a missing thread, an extra thread, or'any other fault there is a variation in the j which allows the cable to be drawn off as the carriage 42 passes from right to left and collects the cable as the carriage passes from left to right. The drum H is shown in Figure as being on the right hand side of the machine, the cable passing from it, beneath the fabric, 'to the carriage 42. In the mechanism shown in Figures 1 to 3, the drum maybe similarly disposed,

or alternatively,'since the cable 10 in this case.

passes over the fabric, it may be disposed in the a middle of the length of the machine above the fabric. The end of the cable I0 is led inwards to the centre of the drum where it is connected by suitable leads 12 to an amplifier which intensifies the variations in current passing through the cell 69 and enables those variations to stop the machine and/or to exhibit a warning signal Having described our invention, what we desire to secure by Letters Patent is 1. A stop or detector motion for a. knitting machine comprising a photo-electric cell, means for traversing said cell repeatedly across the fabric being formed on the machine and close to the line at which the saidfabric is being knitted, means for directing light coming from said fabric into said cell, and operative means controlled by said cell and adapted to give a warning indication on undue variation of the amount of light entering said cell by reason of faulty fabric. 2. A stop or detector motion. for a knitting machine comprising a photo-electric cell, means for traversing saidcell repeatedly across the fabric being formed on the machine and close to the line at which the said fabric is being knitted, means for directing light coming from said fabric into said cell, and operative means controlled by said cell and adapted to stop the machine on undue variation of, the amount of light entering said cell by reason of faulty fabric. I

3. A stop or detector motion for a knitting ma- 1 chine comprising a photo-electric cell, means for traversing said cell repeatedly across the fabric being formed on the machine and close to the line at which the said fabric is being knitted,

means for directing a focused illumination through said fabric and into said cell, and operative means controlled by said cell and adapted to give a warning indication on undue variation of the amount of light entering said cell by reason of faulty fabric.

4. A stop or detector motion for a knitting machine comprising a photo-electric cell, means for traversing said cell repeatedly across the fabric being formed on the machine and close to .the line at which the said fabric is being knitted, a, mirror on the opposite side of said fabric to said cell, means for directing a focused illumi-. nationthrough said fabric to said mirror in such a way that said illumination is reflected from 'said mirror again through said fabric andinto ric into said cell, said .cell having a narrow slit disposed parallel to the length of said fabric for admitting said light, and operative means controlled by said cell and adapted to give a warning indication on undue variation of the amount of light entering said cell'by reason of faulty fabric.

6. A stop or detector motion for a knitting machine comprising a photo-electric cell, means for traversing said cell repeatedly across the fabric being formed on the machine and close to the line at which the said fabric is being knitted, means for directing light coming from said fabric into said cell, means for adjusting the sensitivity of said cell, and operative means controlled and fro along a straight line across the fabricbeing formed on the machine and close to the line at which the said fabric is being knitted, means for directing light coming from said fabric into said cell, and operative means controlled by said cell and adapted to give a warning indication on undue variation of the amount of light entering said cell by reason of faulty fabric.

8. A stop or detectormotionfor a straight bar knitting machine comprising a photo-electric cell, means for traversing said cell repeatedly to and fro along a straight line across the fabric being formed 'on the'machine and close to the line at which said fabric is being knitted, means for directing a focused illumination through said fabric and into said cell, said cell having a narrow slit disposed parallel to the length of said fabric for admitting said light, and operative means controlled by said cell and adapted to stop the Wvhich said fabric is being knitted, a mirror on the opposite side of said fabric to said cell, means for directing a focused illumination through said fabric to said mirror in such a way that said illumination is reflected from said mirror again through said fabric, and into said cell, said cell having a narrow slit disposed parallel to the length of said fabric for admitting said light, and

operative means controlled by said cell and adapt- L ed to stop the machine on undue variation "of the amount oflight entering said cell by reason of faulty fabric. 7 I

' WILLIAM EWART STANLEY.

CYRIL HOUGHTON EDWARDS. 

